Digital display welding mask with HDR imaging

ABSTRACT

A display system for a welding helmet that includes a darkening filter layer, a high-dynamic range (HDR) camera system to capture an HDR light field, and an optical image stabilization subsystem. Captured images are displayed on an HDR electronic display within the welding helmet without risk of overexposure of ultraviolet radiation to the operator. In some examples, dual electronic displays are used to display different HDR images to each eye of the operator.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 63/009,947 titled Digital Display Welding Helmet with HDR LightField Imaging, filed Apr. 14, 2020, which is hereby incorporated byreference in its entirety.

TECHNICAL FIELD

This disclosure relates to welding helmets and welding videography. Inparticular, this disclosure relates to video recording of weldingactivities and welding helmets that utilize an internal electronicdisplay to display a work area to an operator of welding equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

This disclosure includes illustrative embodiments that are non-limitingand non-exhaustive. Reference is made to certain of such illustrativeembodiments that are depicted in the figures described below.

FIG. 1 illustrates a block diagram of example welding mask components,subsystems, and modules, according to one embodiment.

FIG. 2A illustrates an example of a welding mask receiving opticalradiation during the welding of a workpiece, according to oneembodiment.

FIG. 2B illustrates an expanded view of three functional layers of awelding mask, according to various embodiments.

FIG. 2C illustrates a block diagram of three functional layers of awelding mask, according to various embodiments.

FIG. 3A illustrates a functional block diagram of a welding mask withlong-exposure image capture and an electronic display, according tovarious embodiments.

FIG. 3B illustrates a functional block diagram of a welding mask withlong-exposure image capture and dual, digital displays, according tovarious embodiments.

FIG. 4 illustrates a welding mask with multiple cameras that eachinclude three functional layers, according to one embodiment.

FIG. 5A illustrates a multi-camera welding mask with a connected remotecamera, according to one embodiment.

FIG. 5B illustrates a composite video generated by the multi-camerawelding mask, according to one embodiment.

FIG. 5C illustrates an augmented composite video generated by themulti-camera welding mask with one hand of the operator shown partiallytransparent, according to one embodiment.

FIG. 5D illustrates an augmented composite video with the hands of theoperator removed from the workpiece, according to one embodiment.

FIG. 6A illustrates examples of exposure times for capturing frames of avideo, according to various embodiments.

FIG. 6B illustrates additional examples of exposure times for capturingframes of a video, according to various embodiments.

FIG. 6C illustrates additional examples of exposure times for capturingframes of a video, according to various embodiments.

FIG. 6D illustrates additional examples of exposure times for capturingframes of a video, according to various embodiments.

FIG. 7 illustrates an example internal view of a welding mask with dualelectronic displays, according to one embodiment.

FIG. 8 illustrates an augmented video generated by the welding mask withinformational overlay elements, according to one embodiment.

FIG. 9A illustrates high frame rate video capture at various exposurelevels for high dynamic range (HDR) frame compositing, according to oneembodiment.

FIG. 9B illustrates a simplified block diagram of an HDR frame formedfrom three base images at different exposure levels, according to oneembodiment.

FIG. 10A illustrates an example of a welding mask with five camerascapturing images at different exposures and/or perspectives for each eyeof the operator, according to one embodiment.

FIG. 10B illustrates a simplified block diagram of images from multiplecameras combined via HDR frame image processing to generate an HDR videofor each eye of an operator, according to one embodiment.

FIG. 11A illustrates an example of a welding mask with light fieldcameras used to capture light fields for generating video feeds for eacheye of an operator, according to one embodiment.

FIG. 11B illustrates a simplified block diagram of a light field camera,according to one embodiment.

FIG. 11C illustrates a functional block diagram of a welding mask thatutilizes light field images to generate a stereoscopic video feed fordelivery to the eyes of an operator, according to one embodiment.

DETAILED DESCRIPTION

According to various embodiments of the presently described systems andmethods, a welding mask is described that includes a high-dynamic range(HDR) camera subsystem to capture images with relatively long exposureand a darkening layer to attenuate light prior to image capture. Forexample, each frame of a video may be captured with an exposure timethat is longer than one-half of a weld light intensity cycle of awelding machine (referred to herein as a “welder”). The darkening filterfacilitates the long-exposure image captures by preventing overexposure.An optical image stabilization system (e.g., lens-based, software-based,or sensor-based) may be utilized to reduce or eliminate motion blur dueto movement of the welding mask during the relatively long exposuretime. Additional context, variations, and details of such a system areprovided below.

Welding masks (including welding faceplates, helmets, hardhats, etc.)may be manufactured using plastic injection, plastic molding, metals,three-dimensional printing, computer numerical control (CNC) processes,etc. Traditional welding helmets include a window through which anoperator may view the welding workplace. As used herein, the term“operator” encompasses individuals using the welding equipment (e.g., awelder) and users watching someone else using the welding equipment.

Thus, the presently described systems and methods apply to and may beincorporated as part of welding masks or another welding protectiondevice used by a person welding or by other individuals nearby.Similarly, the presently described systems and methods may beincorporated as part of a video system to record the welding process.Any of the various described systems and methods may also be adapted foruse in automated, robotic, or artificial intelligence (AI)-based weldingsystems. For instance, a video system of a robotic welding device mayutilize the systems and methods described herein to generate an improvedvideo feed for use by the robotic welding device. Accordingly, the term“welding mask” is understood to encompass any of a wide variety ofprotection and/or digital imaging devices used by an operator of awelder, bystanders, and/or robotic or other automated welding systemsthat may or may not need the protective elements of a welding mask.

As noted above, traditional welding helmets include a window with adarkening filter to reduce the intensity of the optical radiationgenerated by the workplace and/or reduce or even eliminate certainwavelengths (e.g., dangerous ultraviolet wavelengths and/or infraredwavelengths in the form of heat). Static or fixed darkening filters maymake it easier and safer to view the workspace during a welding process.However, the static or fixed darkening filter may decrease thetransmission of light to such an extent that the operator may not beable to see through the window when the operator is not welding. Somewelding helmets include a pivotable window portion allowing the operatorto raise the window when the operator is not welding and lower thewindow into place when the operator is welding.

Some welding helmets include auto-darkening filers (ADFs) that detect orrespond to the increased optical radiation generated during welding(e.g., increased UV transmission). When the operator is not welding, thewindow may transmit sufficient light to allow the operator to view theworkspace. When the operator begins welding, the window may respond bydarkening and decreasing the transmissivity to a sufficient degree toprotect the operator from overexposure and/or harmful wavelengths.

Static darkening filters may be cumbersome to use because they requirethe operator to reposition the welding mask in place to protect theoperator each time the welding equipment is used. Automatic darkeningfilters respond to the instantaneous increase in optical radiation (orat least some wavelengths of increased optical radiation) when thewelding equipment is used. Even when measured in microseconds ormilliseconds, the response time delay of existing automatic darkeningfilters may expose the operator to bright light and/or harmfulwavelengths for a brief period of time.

According to various examples of the presently described systems andmethods, the window of a welding helmet may be replaced with an HDRcamera subsystem and electronic display system. Specifically, thewelding helmet may include a darkening filter to reduce the intensity ofincident optical radiation and/or filter target wavelengths (e.g.,ultraviolet and/or infrared wavelengths). In some embodiments, multipledarkening filters may be utilized. In some embodiments, automatic orlight-detecting darkening filters may be utilized.

In various embodiments, an HDR camera subsystem captures images of theworkspace and transmits electronic image data to an image processingsubsystem. The image processing subsystem drives an electronic displaywithin the welding helmet to display the captured images of theworkspace to the operator. In some embodiments, dual electronic displaysare utilized to display different images to each eye of the operator.The HDR camera subsystem may include any number of lenses and imagingsensors. Multiple cameras may provide different views of the workspacethat can be stitched or otherwise composited and/or provide differentperspectives of the workspace to each electronic display viewed by theoperator.

For example, images may be composited to make the operator's handstransparent to provide an unobstructed view of a welder wand, aworkpiece, and/or a surrounding workspace. In some embodiments, theoperator's hands, the wand of the welding equipment, and/or anothervisual obstruction, may be made transparent, translucent, or effectivelyremoved from the images displayed to the operator. In some embodiments,welding gloves having markers and/or having identifiable colors may beutilized to make it easier or more efficient for the image processingsubsystem to remove the operator's gloved hands from the displayedimages.

In some embodiments, additional image sensors remotely positionedrelative to the workspace and/or secured to the wand of the weldingequipment may provide additional perspectives. In some embodiments, theadditional image sensors may be used to stitch images together to makeportions of the workspace transparent, translucent, or effectivelyremoved from the images displayed to the operator.

In various embodiments, an optical filter (e.g., an auto darkeningfilter) attenuates the optical radiation to allow for exposure timesmuch longer than would otherwise be possible. For example, a traditionalcamera sensor might capture frames of a video during the very brightwelding process using exposure times on the order of 10 microseconds to1 millisecond. The optical filter allows for exposure times to be usedthat are on the order of 5-30 milliseconds. The optical imagestabilization system operates in conjunction with the imaging sensor toreduce motion blurring during the relatively long exposure times.

The traditional model of capturing images of bright scenes, such as awelding arc, is to decrease the exposure time. The welding arc isgenerated by the welder at an operational frequency (e.g., 100-400 Hz).If an exposure time (e.g., electronic or mechanical shutter) is toolong, the image will be overexposed. If the exposure time is too short,the image will be underexposed. However, if the exposure time in atraditional imaging system is not synchronized with the operationalfrequency of the welding arc, aliasing and/or other artifacts may beintroduced into the image set. For example, some images may be capturedwhen the welding arc is in an “off” or relatively dim portion of thecycle, and other images may be captured when the welding arc is in an“on” or relatively bright portion of the cycle. The resulting video feedof images may appear to flicker or have very dark scenes. Thestroboscopic aliasing of the images captured of the welding arc mayresult in an undesirable video feed that is difficult or even dangerousto use.

In some instances, the operational frequency of the welder maycorrespond directly to or even be equal to the weld light intensitycycle. For example, a welder driven with an alternating current mayexhibit peak light intensity events that correspond to the negativeand/or positive peaks of the alternating current. In other instances,the weld light intensity cycle may be different from the operationfrequency of the welder. For example, the weld light intensity cycle mayvary based on variations in weld material, the welding speed, thedistance between the welding wand and the workpiece, environmentalconditions, and/or other welding condition characteristics. Regardless,the term “weld light intensity cycle” is used herein to refer to thegenerally periodic variation in light intensity exhibited during thewelding process (e.g., a stroboscopic or flickering between highintensity light and low or no light).

Traditional imaging sensors for a video feed may determine that imagesof the welding arc and surrounding workspace should be captured at, forexample, 1/8000^(th) of a second. The camera may capture 60 such imagesper second for a 60-frame-per-second (FPS) video feed. In such anembodiment, each frame of the 60-FPS video feed was captured using anexposure time of 1/8000^(th) of a second. The exact exposure time usedmay depend on the aperture of the camera and the brightness of thescene. However, due to the brightness of the welding arc, the exposuretime of each frame will generally be much shorter than 1/60^(th) of asecond. The resulting stroboscopic aliasing results in an undesirable oreven unusable video feed.

According to various embodiments of the systems and methods describedherein, the HDR camera subsystem may include fixed shade darkeningfilters, auto-darkening filters, and/or tunable auto darkening filters,such as variable shade LCD filters, in front of the camera or cameras toattenuate the brightness of the welding arc. Images can then be capturedfor an entire 1/60^(th) of a second (relatively long exposure) anddelivered as part of a 60-FPS video feed. The exact exposure time andframe rate of the video feed can be adapted for a particularapplication. For example, the images could be captured at 1/50^(th) of asecond or 1/75^(th) of second, and the video feed could be provided at24 FPS, 30 FPS, 60 FPS, or 120 FPS. As long as the exposure time of eachimage is long enough to include at least one “on” cycle of the weldingarc (e.g., one-half of the weld cycle, weld light intensity cycle,and/or the operating frequency), stroboscopic aliasing can be avoided orentirely eliminated.

Thus, in a specific example, an HDR camera subsystem may expose theimage sensor for a defined percentage of the video frame time. Thus, ina system in which the image sensor is exposed for 100% of the videoframe time, a 60-FPS video feed may include 60 images captured for1/60^(th) of a second each (16.6 milliseconds). In various embodiments,optical image stabilization (e.g., digital film stabilization, sensorshifting, lens shifting, or the like) may be utilized to reduce oreliminate any motion blurring due to movement of objects in theworkspace and/or movement of the camera during the relatively longexposure time. Examples of suitable optical image stabilizationtechniques and systems include, but are not limited to, floatingorthogonal lens shift systems, sensor-shift systems, orthogonal transfercharged couple device (CCD) or complementary metal-oxide semiconductor(CMOS) systems, and the like, including combinations thereof.

Thus, according to various embodiments of the presently describedsystems and methods, a welding helmet is described that includes adarkening layer to attenuate light prior to image capture, an HDR camerasubsystem to capture images with an exposure time longer than one cycleof the operating frequency of the welding arc, and an optical imagestabilization system to reduce or eliminate motion blur due to therelatively long exposure time.

The HDR camera subsystem may adjust an effective ISO or gain of adigital sensor and/or adjust an aperture of the camera to attainconsistent exposure levels using constant long-exposure image capture.Alternatively, the HDR camera subsystem may capture images at targetexposure levels by adjusting the aperture, ISO sensor gain, and/orexposure time of each frame, while ensuring that the exposure time ofeach frame is longer than one cycle of the operating frequency of thewelding arc.

In some embodiments, the exposure time may be set at a significantpercentage (e.g., more than 40%, 50%, etc.) of the video frame period.For example, for a 30-FPS video feed, each frame may be captured with anexposure time of approximately 33 milliseconds (for 100%) orapproximately 16 milliseconds (for 50%). For a 60-FPS video feed, eachframe may be captured with an exposure time of approximately 16.6milliseconds (for 100%) or approximately 11.6 milliseconds (for 70%).While the specific exposure time may not be based on the operatingfrequency of the welding arc, the result is that each frame of the videofeed is captured with an exposure time long enough to include one ormore on-cycles of the welding arc. A metal inert gas (MIG) welder may,for example, include a welding arc operating at 100 Hz with a10-millisecond cycle, with on-cycles occurring every 5 milliseconds.Video frames (images) captured with exposure times in excess of 5milliseconds would include at least one on-cycle.

According to various embodiments, the HDR camera subsystem may utilizeone or more imaging sensors with global electronic shutters, mechanicalshutters, rolling electronic shutters, or the like. In variousembodiments, the HDR camera subsystem may include any number of CCDand/or CMOS sensors. Digital film sensors, including digital filmsensors with integrated optical image stabilization, may be utilized aswell.

According to some embodiments of the systems and methods describedherein, the HDR camera subsystem may, for example, include a camera tocapture images at 120 or 240 frames per second (or higher) and thendeliver only those frames that were captured with a desirable or targetexposure level as part of a 30 or 60 FPS video feed. For instance, onlycaptured images having a target or substantially uniform averagebrightness level may be included as part of the video feed.

In other embodiments, one or more cameras are utilized to capture someimages having relatively short exposures and other images havingrelatively long exposures. The short-exposure (darker) and long-exposure(lighter) images may be combined to create hybrid exposure images orhigh-dynamic range images that can be used as the frames for ahigh-dynamic range video feed. High-dynamic range videos allow fordarker portions of the workspace to appear relatively lighter andlighter portions of the workspace (e.g., the welding arc) to appearrelatively darker.

In some embodiments, the HDR camera subsystem may include multipleimaging sensors that capture images of the workplace at differentexposure levels. In some instances, different imaging sensors may beassociated with darkening filters of varying attenuation, differenteffective sensor gain (ISO) values, different apertures, and/ordifferent exposure times. Images at different overall brightness levelsmay be combined to generate a high dynamic range (HDR) image of theworkspace. Multiple HDR images may be delivered as frames of a videofeed to an internal display of the welding helmet.

As a specific example, the HDR camera subsystem may include five camerasfor each eye of the operator (10 cameras total). Each of the fivecameras may capture images at different exposure levels. In examples inwhich the capture frame rate is the same as the display frame rate, fivecaptured images may be combined to form an HDR image that can bedelivered as a video frame to the electronic display for one eye of theoperator. In examples in which the capture frame rate is higher than thedisplay rate, any number of captured images may be combined to form HDRimages for delivery as video frames to one eye of the operator. In aspecific embodiment, five cameras may be positioned on the weldinghelmet in the approximate location of each eye of the operator, for atotal of 10 cameras.

In some embodiments, a relatively high frame rate (e.g., 120 FPS or 240FPS) may be used to capture images of a workspace with a constantexposure, including a constant exposure time. The video feed provided tothe operator of the welding helmet may view one or more LCD or otherelectronic displays at 30 or 60 FPS. Accordingly, multiple capturedframes may be combined into a single frame of the delivered video feed.In some instances, a best captured frame (e.g., frame closest to atarget exposure or brightness level or a frame with the leastblack/white clipping) may be selected to the exclusion of the otherframes for delivery as part of the video feed. In other embodiments,multiple frames of a constant exposure time (but different exposures viadifferent darkening filter levels, apertures, and/or sensor gain values)may be combined to form an HDR frame for delivery to the electronicdisplay(s). In still other embodiments (as previously described),multiple frames of different exposure times (e.g., short exposure timesand long exposure times) may be combined to form HDR frames for deliveryto the electronic displays.

In yet another specific example, five cameras may be associated witheach eye of the operator to capture images at 120 FPS. Two electronicdisplays may display video feeds (e.g., stereoscopic video feeds) to theeyes of the operator at 30 FPS. Accordingly, 20 captured images may becombined to form a single HDR image for each frame of the video feeddelivered to each eye of the operator. As previously described, internalelectronic displays, such as LCD and/or OLED displays, within thewelding helmet may display the video feed to the operator. Stereoscopicdisplays may provide slightly different perspectives to each eye of theoperator. The resulting video feed is effectively a three-dimensionalview of the workspace.

In any of the various embodiments described herein, the electronicdisplay(s) within the welding helmet may display images (e.g., HDRimages of the workspace) that are augmented to provide additionalinformation. For example, the video feed may be augmented to includeinformation relating to the welding process, such as temperaturereadings, warnings, welding speed, tips, etc.

In some embodiments, additional sensors may provide additionalinformation that may also be overlaid on the video feed. For example, anultrasonic sensor system may detect the quality of the weld, and thevideo feed may be overlaid or otherwise augmented to include anindication of the weld quality. For example, a numerical value may bedisplayed within the video feed to indicate a weld quality ortemperature. Alternatively, the weld in the video feed may be overlaidor augmented to include color overlays on the weld itself indicative ofthe weld quality, temperature, or other measurement data.

In still other embodiments, the camera system may include light fieldcameras (also known as plenoptic cameras) that capture information aboutthe direction from which the light rays are received in addition tointensity information. Captured images that include the direction fromwhich the light rays were received can be combined to form HDR images inwhich the intensity levels of received optical rays from differentlocations within the workspace are combined. Location-based HDR images(e.g., HDR images based on the angle of incidence at which the lightrays are received) may be processed to form the frames of the video feeddisplayed via an LCD or OLED electronic display.

In various examples, after the light field is captured, software is usedto reverse the light rays that each camera captured to their ‘source’ in3D space. After reversing the light rays to determine their source in 3Dspace, a new virtual perspective is ‘rendered’ by combining differentlight rays from different cameras in various proportions. Because thedifferent cameras contained different exposures, the final image usedfor each frame of the video possesses a much higher dynamic range thanthe source images alone.

As described herein, the high dynamic range scene created by the weldingarc relative to the ambient light in the surrounding workspace may bevery difficult to capture using standard camera systems. Accordingly,discrete image sensors placed in close proximity to one another (e.g.,1″ or less) may be used to capture images of the scene simultaneously atvarious exposure levels that cover the total dynamic range of the scene.As described herein, each camera or imaging sensor captures a uniqueperspective of the scene at a unique exposure. The resulting set ofthese images, when combined with knowledge of each camera's positionrelative to the workspace, constitutes a light field as the resultinginformation defines the intensity and direction of light following fromdifferent parts of the scene.

Furthermore, in various embodiments, the HDR image formed from themultiple images may be virtually rendered from any perspective withinthe group of real cameras (e.g., the five cameras associated with eacheye). While traditional light field cameras may capture images at thesame exposure level, the proposed implementation in which normal imagesensors arranged in close proximity capture the light field data atdifferent exposure levels avoids the use of specialized optics orspecialized sensors.

The different exposure levels of the cameras associated with each eye ofthe operator can be captured by using different levels of darkeningfilters for each image sensor, adjusting an aperture (e.g., via aniris), using sensors with different gains, using different f-stops,adjusting brightness sensitivity settings, adjusting exposure times, andthe like. Captured images may be rendered using an FPGA, a GPU,specialized application specific integrated circuits, and/or artificialintelligence processing cores.

Some of the infrastructure that can be used with embodiments disclosedherein is already available, such as: general-purpose computers,microprocessors, lens systems, cameras, image sensors, batteries, powersupplies, LCD displays, OLED displays, computer programming tools andtechniques, digital storage media, and communications networks. Acomputer or processing system may include a processor, such as amicroprocessor, microcontroller, logic circuitry, or the like. Theprocessor may include a special purpose processing device, such as anASIC, PAL, PLA, PLD, FPGA, or other customized or programmable device.The computer or processing system may also include a computer-readablestorage device, such as non-volatile memory, static RAM, dynamic RAM,ROM, CD-ROM, disk, tape, magnetic, optical, flash memory, or othercomputer-readable storage medium.

Aspects of certain embodiments described herein may be implemented asusing microprocessors, microcontrollers, general-purpose computers,industrial-computers, FPGAs, discrete electrical components, surfacemount components, or ASICs. Aspects of certain embodiments describedherein may be implemented as software modules or components. As usedherein, a software module or component may include any type of computerinstruction or computer executable code located within or on acomputer-readable storage medium. A software module may, for instance,comprise one or more physical or logical blocks of computerinstructions, which may be organized as a routine, program, object,component, data structure, etc. that perform one or more tasks orimplement particular abstract data types.

A particular software module may comprise disparate instructions storedin different locations of a computer-readable storage medium, whichtogether implement the described functionality of the module. Indeed, amodule may comprise a single instruction or many instructions and may bedistributed over several different code segments, among differentprograms, and across several computer-readable storage media. Someembodiments may be practiced in a distributed computing environmentwhere tasks are performed by a remote processing device linked through acommunications network. In a distributed computing environment, softwaremodules may be located in local and/or remote computer-readable storagemedia. In addition, data being tied or rendered together in a databaserecord may be resident in the same computer-readable storage medium, oracross several computer-readable storage media, and may be linkedtogether in fields of a record in a database across a network.

Some of the embodiments of the disclosure can be understood by referenceto the drawings, wherein like parts are generally designated by likenumerals. The components of the disclosed embodiments, as generallydescribed and illustrated in the figures herein, could be arranged anddesigned in a wide variety of different configurations. Thus, thefollowing detailed description of the embodiments of the systems andmethods of the disclosure is not intended to limit the scope of thedisclosure, as claimed, but is merely representative of possibleembodiments. Well-known structures, materials, or operations are notshown or described in detail to avoid obscuring aspects of thisdisclosure. In addition, the steps of a method do not necessarily needto be executed in any specific order, or even sequentially, nor need thesteps be executed only once, unless otherwise specified.

FIG. 1 illustrates a block diagram of example welding mask components,subsystems, and modules, according to one embodiment. As illustrated,welding mask imaging components and electronic system 100 may include abus 120 that connects a processor 130, a memory 140, a network interface150, and various hardware subcomponents and computer-readable storagemedium modules 170.

The hardware subcomponents and computer-readable storage medium modules170 may include one or more of an HDR camera subsystem 180, an imagestabilization subsystem 182, an optical filter 184, a video controller186, a digital electronic display 188, a weld cycle detection subsystem189, and a welder interface subsystem 191.

The HDR camera subsystem 180 may, for example, include a multipixeldigital imaging sensor to capture images as frames of a video. The HDRcamera subsystem 180 may further include an integrated video controllerand/or be connected to an external video controller. In someembodiments, the processor 130 may implement computer-executableinstructions stored in a non-transitory computer-readable medium toimplement the operations and functions described herein in connectionwith the video controller 186. The video controller 186 may cause theHDR camera subsystem 180 to capture each frame of the video with anexposure time selected as a function of a weld cycle of a welder (e.g.,a weld light intensity cycle, and/or the operating frequency). Forexample, the exposure time may be selected as a percentage of the weldcycle (e.g., as a percentage of the weld light intensity cycle). Invarious embodiments, the exposure time is selected to include at leastone half of a weld cycle or weld light intensity cycle of the welder toensure that at least one peak illumination event by the weld arc iscaptured during the exposure. In some instances, the exposure time maybe selected as a complete duration of each frame of the video.

Specific examples of possible frame rates and exposure times include butare not limited to 24 frames per second with an exposure time of atleast 40 milliseconds, 30 frames per second with an exposure time of atleast 33 milliseconds, 48 frames per second with an exposure time of atleast 20 milliseconds, 60 frames per second with an exposure time of atleast 16 milliseconds, and 120 frames per second with an exposure timeof at least 8 milliseconds. In some instances, the exposure times may bedecreased slightly to accommodate for data transmission, storage, andprocessing times. For example, a 100% exposure time for a frame rate of60 frames per second would mathematically 16.66 milliseconds, howeverthe system may utilize a 84-90% exposure time of 14 or 15 millisecondsto allow some time for data transmission, storage, and processing.

Accordingly, some additional possible frame rates and exposure timesinclude, but are not limited to 24 frames per second with an exposuretime of at least 38 milliseconds, 30 frames per second with an exposuretime of at least 31 milliseconds, 48 frames per second with an exposuretime of at least 18 milliseconds, 60 frames per second with an exposuretime of at least 14 milliseconds, and 120 frames per second with anexposure time of at least 6 milliseconds.

As noted above, traditional imaging approaches that utilize shortexposures must be synchronized with the weld cycle (operationalfrequency) to avoid stroboscopic aliasing. The approach describedherein, including in conjunction with FIG. 1 , can be implemented as anasynchronous video capture system that captures frames of the videoasynchronously with respect to the operating frequency of the welder. Insome instances, the brightness of the light generated during each weldcycle is nonlinear with respect to current. In such embodiments, thevideo controller 186 may cause the HDR camera subsystem 180 to captureeach frame of the video with an exposure time selected as a multiple ofa half weld cycle or weld light intensity cycle of the welder to ensurethat an equal number of peak illumination events are captured duringeach exposure. In some embodiments, the video controller 186 may causethe HDR camera subsystem 180 to capture each frame of the video with anexposure time selected to include multiple weld cycles or weld lightintensity cycles of the welder, with an equal number of peakillumination events captured during each exposure.

In some embodiments, the video controller 186 may receive dataidentifying an operational frequency of the welder. For example, awelder interface subsystem 191 may be in communication with the welder(e.g., wired or wireless) and receive information identifying aninstantaneous operation frequency and/or other welder operationalinformation. The video controller 186 may use the data to select anexposure time as a submultiple of the identified operational frequencyof the welder. In other embodiments, the system may include a weld cycledetection subsystem 189 to detect a duration of each weld cycle or weldlight intensity cycle. The detected weld cycle or weld light intensitycycle information may be transmitted to the video controller 186 for usein selecting an exposure time.

According to various embodiments, the HDR camera subsystem 180 and thevideo controller 186 may capture light fields using light field cameras(e.g., plenoptic cameras). Alternatively, the light field data may becaptured using a plurality of discrete image sensors placed in closeproximity to one another (e.g., 1″ or less) to capture images of thescene simultaneously at various exposure levels and at differentperspectives that cover the total dynamic range of the scene.

In embodiments in which multiple discrete image sensors are used tocapture the light field, computational processing is used to derive thelight field data from the images captured by each image sensor based oneach camera's relative position. The light field information can beprocessed to generate an HDR image that is virtually rendered from anyperspective within the group of real cameras (e.g., the five camerasassociated with each eye). While traditional light field cameras maycapture images at the same exposure level, the proposed implementationin which normal image sensors arranged in close proximity capture thelight field data at different exposure levels avoids the use ofspecialized optics or specialized sensors.

The image stabilization subsystem 182 may compensate for movement of thewelding mask or other components during image capture. In someembodiments, the image stabilization subsystem 182 comprises an opticalimage stabilization lens system in which at least one lens element moveswith respect to another lens element. In some embodiments, the imagestabilization subsystem 182 comprises an image sensor stabilizationsubsystem in which the image sensor physically moves relative to a lenselement of the digital imaging sensor.

The optical filter 184 attenuates at least some wavelengths of opticalradiation (e.g., visible light, UV light, infrared light, etc.). Theattenuation may be the same for all wavelengths or different dependingon wavelength. For example, UV and infrared light may be effectivelyremoved, while visible light may be attenuated sufficient forlong-exposure imaging. In some embodiments, the optical filter is anauto-darkening filter (ADF). In some embodiments, the optical filter 184is a tunable auto-darkening filter. The video controller 186 may tunethe tunable auto-darkening filter to selectively attenuate the opticalradiation to achieve a target exposure of each frame of the video forthe selected exposure time.

The digital electronic display 188 may be positioned within a protectiveshell of the welding mask or in a remote location for viewing by remotepersons and/or computerized and automated welding machines. In variousembodiments, the digital electronic display 188 is positioned within thewelding mask and displays the video of the welding process to theoperator.

In some embodiments, the video controller 186 may implement functions ofa video processing system. For example, the video controller 186 may beor include a video processing subsystem to generate digitally renderedcomposite video using multiple frames of videos from multiple cameras.For example, the video controller 186 may digitally render a compositevideo to form an augmented reality (AR) video with an informationaloverlay. A weld monitoring subsystem may detect welding characteristicsof the welding process. The information overlay may display one or moreof the detected welding characteristics. For example, the informationaloverlay in the composite AR video may display a weld pool size, awelding current, a visual indicator to direct the operator to speed up,an indicator to slow down, a suggestion to add material, a temperature,and/or a quality metric.

As previously described, variations of the imaging systems describedherein may be utilized in conjunction with automated, robotic, orcomputerized welding systems. In such instances, the protective elementsof the mask may be unnecessary. In such cases, the welding imagingsystem may include an HDR camera subsystem 180 with at least one camerato capture images as frames of a video. The HDR camera subsystem 180 mayinclude or operate in conjunction with an optical filter 182 toattenuate at least some wavelengths of optical radiation generated by awelder during a welding process. The HDR camera subsystem 180 mayinclude or operate in conjunction with an image stabilization subsystem182 to compensate for movement of the welding mask during image captureby the HDR camera subsystem 180. A video processing subsystem may storethe video in a data store (e.g., a database, server, data storage, etc.)and/or transmit the video to a remote location for viewing and/orprocessing.

FIG. 2A illustrates an example of a welding mask 200 receiving opticalradiation 225 during the welding of a workpiece 210 (shown as two metalplates) by a welder 205 (only a welder wand is shown). Optical radiation225 is incident on the window 250 of the welding mask 200. As describedherein, instead of a traditional window 250, the welding mask includes amulti-layer imaging system that includes a darkening optical filter, anHDR camera subsystem to capture long-exposure images, and an imagestabilization subsystem.

FIG. 2B illustrates an expanded view of three functional layers 251-253of the “window” portion 250 of the welding mask 200, according tovarious embodiments. The three functional layers 251-253 may not beembodied as actual layers of a window. Instead, a first layer representsa darkening optical filter 251, such as an auto-darkening opticalfilter. A second layer represents an optical image stabilization layer252. A third layer represents an HDR camera subsystem 253 that mayinclude one or more cameras to capture relatively long exposures.Specifically, the images captured by the cameras can have exposure timeslonger than would otherwise be possible with the same sensors because ofthe initial darkening optical filter layer 251 and optical imagestabilization layer 252.

FIG. 2C illustrates a block diagram of the three functional layers251-253 of the “window” portion 250 of the welding mask 200 describedabove. Specifically, the darkening filter 251 is illustrated as aninitial layer to reduce the intensity of visible light generated by thewelding arc and reduce or even eliminate the ultraviolet wavelengths. Anoptical image stabilization lens system 252 compensates for the motionof objects in the workspace and/or motion of the welding mask duringimage capture. Finally, a long-exposure image sensor of the camerasubsystem 253 captures images having a relatively long exposure time, asdescribed herein.

FIG. 3A illustrates a functional block diagram of a digital displaywelding mask 300 with long-exposure image capture, according to variousembodiments. As illustrated, a darkening filter 351, optical imagestabilization lens system 352, and long-exposure image sensor 353 areused to capture images on one side of a welding mask 300 (illustrated asa black bar). Inside the mask 300 (to the right of the black bar), animage processing subsystem 360 may process the images (as described inconjunction with FIG. 1 ) and render them for display on an electronicdisplay 375 visible by the eye 390 or eyes of the operator within thewelding mask 300.

While many of the examples described herein are provided in the contextof a welding mask 300 utilizing an internal electronic display 375, itis appreciated that the presently described systems and methods may alsobe utilized for video recording of welding activities. For example, avideo camera may be used to capture video of a welding process. Thewelding video system may, for example, be part of a handheld device, afixed or mounted recording system, and/or a portable video recordingsystem. In some examples, the welding video system may be integrated aspart of personal protection equipment (PPE). The welding video systemmay include any number of cameras and operate according to anycombination of the various systems and methods described herein.

FIG. 3B illustrates a functional block diagram of a dual-display digitalwelding mask 300 with long-exposure image capture, according to variousembodiments. Again, a darkening filter 351, optical image stabilizationlens system 352, and long-exposure image sensor 353 are used to captureimages on one side of a welding mask 300 (illustrated as a black bar).Inside the mask 300 (to the right of the black bar), an image processingsubsystem 360 may process the images (as described in conjunction withFIG. 1 ) and render them for display via two different electronicdisplays 375 and 376 (e.g., as a stereoscopic display) that provideimages from slightly different perspectives to each eye 390 and 391 ofthe operator.

FIG. 4 illustrates a multi-camera welding mask 400, each camera of whichincludes three functional layers, according to one embodiment. Asillustrated, the multi-camera welding mask 400 includes four cameras401, 402, 403, and 404. Each of the four cameras is associated with anindividual darkening filter 451, optical image stabilizing lens system452, and a long exposure image sensor 453. In some embodiments, a singleor “global” darkening filter 451 and/or single or “global” optical imagestabilizing lens system 452 may be utilized in conjunction withindividual long exposure image sensors of the four cameras 401, 402,403, and 404. The workpiece 410 may be imaged by the four cameras 401,402, 403, and 404 during the welding process. The operator may hold theworkpiece 410 with a left hand 413 and a welder wand 405 with a righthand 412.

The illustrated example of four cameras in a multi-camera welding mask400 is merely one example of many possible camera arrangements. Anynumber of cameras may be utilized and positioned in various locations onor off (e.g., remotely) of the welding mask 400 to capture images,frames of a video, and/or provide a direct video feed from variousperspectives relative to the workpiece 410 and welder wand 405.

FIG. 5A illustrates a multi-camera welding mask 500 with a connectedremote camera 505, according to one embodiment. As illustrated, fourcameras 501, 502, 503, and 504 may be positioned on the welding mask 500to capture four perspectives of the workpiece 510 during the weldingprocess by the welder wand 505. The remote camera 505 may be connectedto the processing components and other electronics of the welding mask500 (e.g., wirelessly or via a wire). The welding mask 500 may utilizethe five video feeds to render composite video for display as part of asingle video feed or as dual video feeds (e.g., stereoscopic video) tothe operator.

The multiple on-mask cameras 501, 502, 503, and 504 and the remotecamera 505 may provide different views of the workspace and workpiece510 that can be stitched or otherwise composited. For example, imagesfrom the multiple cameras 501-505 may be composited to make theoperator's hands 512 and 513 transparent to provide an unobstructed viewof the welder wand 505, the workpiece 510, and/or the surroundingworkspace. In some embodiments, the operator's hands 512 and 513, thewelder wand 505, and/or another visual obstruction, may be madetransparent, translucent, or effectively removed from the imagesdisplayed to the operator. In some embodiments, the operator may wearwelding gloves having markers (e.g., lines, colors, stripes, QR codes,etc.) and/or having identifiable colors (e.g., green) that make iteasier or more efficient for the welding mask 500 to remove theoperator's gloved hands from the displayed images (e.g., frames of thevideo feed).

FIG. 5B illustrates a composite video on an electronic display 575generated by the multi-camera welding mask 500 of FIG. 5A, according toone embodiment. In the illustrated embodiment, the workpiece ispartially obstructed by the operator's left hand 513. The right hand 512is visible gripping the welder wand 505.

FIG. 5C illustrates an augmented composite video on the electronicdisplay 575 generated by the multi-camera welding mask 500 of FIG. 5A.As illustrated, the left hand 513 of the operator is shown at leastpartially translucent so that the workpiece 510 can be viewed moreclearly, according to one embodiment.

FIG. 5D illustrates an augmented composite video on the electronicdisplay 575 with both hands 512 and 513 of the operator removed from theworkpiece 510 and welder wand 505, according to one embodiment.

FIG. 6A illustrates examples of exposure times for capturing frames of avideo, according to various embodiments. A legend 600 identifies shadingpatterns for welding cycle intensity peaks, the duration of each frame,and the duration of exposure during each frame. The horizontal axisrepresents time on the scale of a 100 Hz operational frequency of awelder. As illustrated, the welder shows weld cycle intensity peaks 613(e.g., peak brightness events) at positive and negative peaks every 5milliseconds for the 10-millisecond wavelength.

The top graph shows an example of a 120 frame per second (FPS) videocapture 611 with 1 millisecond exposures used for each frame. Asillustrated, the exposure time of the first frame of the 120 FPS videocapture 611 coincides with a weld cycle peak 613. However, due to a lackof synchronization and the short exposure time (e.g., less than one halfof a weld cycle), the exposure time of the second frame of the 120 FPSvideo capture 611 is not aligned with a weld cycle peak 613.Accordingly, the second frame of the 120 FPS video capture 611 will bemuch darker than the first frame of the 120 FPS video capture 611. Assuch, the graph of the 120 FPS video capture 611 provides an example ofa video capture approach that results in undesirable flickering orstroboscopic aliasing.

One possible approach to avoid the undesirable flickering orstroboscopic aliasing is to use a video frame rate that corresponds tothe operational frequency of the welder. However, this approach requiresthat the relatively short exposure time be synchronized with the weldcycle peak 613. The graph of the 100 FPS video capture 612 showsrelatively short, 1 millisecond exposure times. As illustrated, a lackof synchronization results in the exposure of every frame being offsetwith respect to the weld cycle peaks. The resulting video may beunderexposed and/or not capture images of the weld arc at all.

FIG. 6B illustrates additional examples of exposure times for capturingframes of a video, according to various embodiments. According tovarious embodiments of the systems and methods described herein,relatively long exposures (e.g., exposures that are at least one half ofa weld cycle or weld light intensity cycle) allow for improved videocapture with correctly exposed frames without any flickering orstroboscopic aliasing. The graph of image capture at 100 FPS with5-millisecond exposures 621 shows that that exposure of each of frames1-5 includes exactly one complete weld cycle peak in the graph of weldcycle peaks 623.

The graph of asynchronous image capture at 100 FPS with 5-millisecondexposures 622 demonstrates that each exposure still includes onecomplete weld cycle peak. In some instances, the exposure may include aportion of one weld cycle peak and a portion of another weld cycle peakthat additively equate to a single weld cycle peak.

FIG. 6C illustrates additional examples of exposure times for capturingframes of a video, according to various embodiments. As illustrated, a60 FPS video capture with 5-millisecond exposures 631, a 60 FPS videocapture with 10-millisecond exposures 632, an offset or asynchronous 60FPS video capture with 5-millisecond exposures 633 all include frameswith an equal number of weld peak cycles 634. Accordingly, each of theserelatively long-exposure video capture schemas allows for a flicker-freevideo.

FIG. 6D illustrates additional examples of exposure times for capturingframes of a video, according to various embodiments. Again, weld cyclepeaks 643 for a 100 Hz operation frequency are illustrated along thehorizontal time axis. A synchronized 60 FPS video capture with15-millisecond exposures 641 is illustrated in which each frame includesthree weld cycle peaks. The relatively long exposure ensures thatsynchronization is unnecessary. Accordingly, asynchronous 60 FPS videocapture with 15-millisecond exposures 642 also captures 3 weld cyclepeaks in each frame.

FIG. 7 illustrates an example internal view of a welding mask 700 withdual electronic displays 775 and 776, according to one embodiment. Insome embodiments, the dual electronic displays 775 and 776 may displaystereoscopic images to the operator that allow for three-dimensionalrendering of the welding process.

FIG. 8 illustrates an augmented video generated by the welding mask anddisplayed within an electronic display 875. The augmented video mayinclude “real” elements, such as the workpiece 810 and a weld wand 805with informational overlay elements, according to various embodiments.In the illustrated example, the informational overlay includes a speedarrow suggesting that the operator increase the welding speed. Atemperature sensor may detect a weld temperature and the temperature maybe overlaid as part of the informational overlay. Additionally, a weldquality indicator indicates that the weld quality is 80%.

For example, a weld monitoring subsystem may monitor the weld based onvisual appearance, ultrasonic density monitoring, weld temperatureconsistency, and/or the like. The weld quality indicator may indicate aweld quality based on one or more weld characteristics being within athreshold range of an optimal value. The weld quality metric may beoverlayed on the video feed as a percentage, a “good” or “bad”annotation, a star rating, a numerical value, a letter grade, a bargraph, and/or the like.

FIG. 9A illustrates high frame rate video capture at various exposurelevels for HDR frame compositing, according to one embodiment. Theillustrated embodiment includes weld cycle peaks 913 of a welderoperating at a 200 Hz operational frequency. While any of a wide varietyof specific frame rates may be used for image capture and/or videodelivery, the illustrated example utilizes 240 FPS. A first videocapture at 240 FPS 911 with an exposure time equal to 100% of the frameduration may be utilized to image the weld arc. The workpiece andsurrounding work area may appear very dark in the image due to the otherexposure settings (e.g., the ISO equivalent, aperture, and associateddarkening optical filter). A second video capture at 240 FPS 912 with anexposure time equal to only 15% of the frame duration may be used toimage the workpiece and/or surrounding work area.

As illustrated, the imaging frame rate of 240 FPS 912 is notsynchronized with the welder operational frequency of 200 HZ.Accordingly, frames 1, 5, 7, and 9 are moderately exposed, frames 2, 4,6, 8, and 10 are overexposed, and frames 3 and 11 are underexposed.Those frames that correctly expose the workpiece and/or surrounding workarea may be combined with the images of the weld arc from the firstvideo capture at 240 FPS 911 to generate HDR images. Those frames thatare overexposed or underexposed may be discarded or used to furtherextend the range of the HDR images.

FIG. 9B illustrates a simplified block diagram of an HDR frame 940formed from three base images 921, 922, and 923 at different exposurelevels, according to one embodiment. The HDR approach illustrated inFIG. 9B in which multiple images are combined to generate an HDR imagemay be utilized. However, as described herein, multiple image sensorsmay be utilized to calculate or generate light field data. Rather thancombining images from the image sensors to generate an HDR image, thesystem may directly generate an HDR frame for the HDR video using thelight field data.

FIG. 10A illustrates an example of a welding mask 1000 with five cameras1001 and 1002 capturing images at different exposures and/orperspectives for each eye of the operator, according to one embodiment.Each camera may capture a different perspective of the workpiece 1010,hands 1012 and 1013, and welder wand 1005. Each camera may also captureimages at a different exposure level. The welder system may determinelight field data for the scene (the workpiece 1010, hands 1012 and 1013,and welder wand 1005) based on the relative locations of the discretecameras 1001 and 1002. The light field data may be used to directlygenerate HDR images.

FIG. 10B illustrates a simplified block diagram of images from multiplecameras combined via HDR frame image processing to generate an HDR videofor each eye of an operator, according to one embodiment. Asillustrated, five “left-eye” cameras 1001 capture images at 120 FPS toprovide light field data to the system. An HDR frame image processingsubsystem 1050 processes the light field data to generate an HDR frame.An HDR video 1060 is generated at 30 FPS that is fed to the left eye1090 of the operator via a left eye electronic display 1075.

Similarly, five “right-eye” cameras 1002 capture images at 120 FPS toprovide light field data to the system. An HDR frame image processingsubsystem 1051 processes the light field data to generate an HDR frame.An HDR video 1061 is generated at 30 FPS that is fed to the right eye1091 of the operator via a right eye electronic display 1076.

FIG. 11A illustrates an example of a welding mask 1100 with light fieldcameras 1101 and 1102 (e.g., plenoptic cameras) to directly capturelight fields that can be used to generate HDR frames for HDR video feedsfor each eye of an operator.

FIG. 11B illustrates a simplified block diagram of light field cameras1101 and 1102, according to one embodiment. As illustrated, each lightfield camera 1101 and 1102 may include a main lens, a microlens array,and a photosensor. Any of a wide variety of alternative plenoptic orother types of light field camera designs may be utilized.

FIG. 11C illustrates a functional block diagram of a welding mask thatutilizes light field images 1150 and 1151 to generate a stereoscopicvideo feed for delivery to the eyes of an operator, according to oneembodiment. As illustrated, the light field images 1150 and 1151 areprocessed via an image processing converter 1160 and 1161 to generateHDR video at 30 FPS 1170 and 1171. The HDR video at 30 FPS 1170 and 1171is displayed via left eye and right eye electronic displays 1175 and1176.

The examples and illustrations provided relate to specific embodimentsand implementations of a few of the many possible variations. It isunderstood that this disclosure is not limited to the preciseconfigurations and components disclosed herein and that some embodimentsmay be combined and/or elements may be omitted from describedembodiments. Accordingly, many changes may be made to the details of theabove-described embodiments without departing from the underlyingprinciples of this disclosure. The following claims are part of thepresent disclosure, are expressly incorporated into the detaileddescription, and are consistent with the various embodiments orcombination of embodiments described herein. The scope of the presentinvention should, therefore, be determined in the context of and to atleast encompass the claims below.

What is claimed is:
 1. A welding mask, comprising: a protective shell to provide physical protection to an operator of a welder; a high-dynamic range (HDR) camera subsystem to: receive data identifying an operational frequency of the welder; select an exposure time as a submultiple of the identified operational frequency of the welder; generate HDR frames of an HDR video using at least one image captured with the selected exposure time; an image stabilization subsystem to compensate for movement of the welding mask during image capture; an optical filter to attenuate at least some wavelengths of optical radiation; and a digital electronic display positioned within the protective shell to display the HDR video to the operator.
 2. A welding mask, comprising: a protective shell to provide physical protection to an operator of a welder; a high-dynamic range (HDR) camera subsystem to generate HDR frames of an HDR video; an image stabilization subsystem to compensate for movement of the welding mask during image capture, wherein the image stabilization subsystem comprises an image sensor stabilization subsystem in which the image sensor physically moves relative to a lens element of the HDR camera subsystem; an optical filter to attenuate at least some wavelengths of optical radiation; and a digital electronic display positioned within the protective shell to display the HDR video to the operator.
 3. The welding mask of claim 2, wherein the HDR camera subsystem comprises a bracketing imaging system to capture multiple images at different exposures that are combined to generate each HDR frame of the video.
 4. The welding mask of claim 1, wherein the HDR camera subsystem is configured to generate a first HDR video for a right eye of the operator and a second HDR video for the left eye of the operator, and wherein the digital electronic display comprises a stereoscopic display to display the first HDR video to the right eye of the operator and the second HDR video to the left eye of the operator.
 5. The welding mask of claim 2, wherein the camera subsystem is an asynchronous video capture system that captures frames of the video asynchronously with respect to an operating frequency of the welder.
 6. The welding mask of claim 2, wherein each frame of the HDR video generated by the camera subsystem comprises at least one image captured with an exposure time that includes at least one half of a weld light intensity cycle of the welder.
 7. The welding mask of claim 2, wherein each frame of the HDR video generated by the camera subsystem comprises at least one image captured with an exposure time that includes a single weld light intensity cycle of the welder.
 8. The welding mask of claim 2, wherein each frame of the HDR video generated by the camera subsystem comprises at least one image captured with an exposure time that includes multiple weld light intensity cycles of the welder.
 9. The welding mask of claim 2, wherein the HDR camera subsystem is configured to: receive data identifying an operational frequency of the welder; and select the exposure time of at least one image used to generate each HDR frame of the HDR video as a submultiple of the identified operational frequency of the welder.
 10. The welding mask of claim 9, further comprising a weld cycle detection subsystem to: detect a duration of each weld light intensity cycle of the welder, and transmit data identifying the detected weld light intensity cycle duration to the HDR camera subsystem.
 11. The welding mask of claim 9, further comprising a welder interface subsystem to: receive data from the welder identifying the operational frequency, and relay the data from the welder identifying the operational frequency to the HDR camera subsystem.
 12. The welding mask of claim 2, wherein the HDR camera subsystem is configured to generate the HDR video with a frame rate that is a submultiple of the operational frequency of the welder.
 13. The welding mask of claim 1, wherein the optical filter comprises an auto-darkening filter (ADF).
 14. The welding mask of claim 1, wherein the image stabilization subsystem comprises an optical image stabilization lens system in which at least one lens element moves with respect to another lens element.
 15. The welding mask of claim 2, wherein the HDR camera subsystem comprises an HDR light field imaging system to capture an HDR light field used to generate each HDR frame of the video.
 16. The welding mask of claim 1, wherein the optical filter comprises a tunable auto-darkening filter, and wherein the HDR camera subsystem tunes the tunable auto-darkening filter to selectively attenuate the optical radiation to achieve a target exposure of each frame of the video for the selected exposure time.
 17. A welding mask, comprising: a protective shell to provide physical protection to an operator of a welder; a high dynamic range (HDR) camera subsystem with a plurality of cameras to: receive data identifying an operational frequency of the welder; select an exposure time for each camera that is a submultiple of the identified operational frequency of the welder; and capture multiple images to generate HDR images as frames of videos from multiple perspectives at the selected exposure time for each respective camera; wherein the HDR camera subsystem includes: at least one auto-darkening filter (ADF) to attenuate at least some wavelengths of optical radiation generated during a welding process by the welder, and an image stabilization subsystem to compensate for movement of the welding mask during image capture by each of the plurality of cameras, wherein the image stabilization subsystem comprises an image sensor stabilization subsystem in which the image sensor physically moves relative to a lens element of the HDR camera subsystem; a video processing subsystem to generate a digitally rendered composite HDR video using the videos from the plurality of cameras; and a digital electronic display positioned within the protective shell to display the digitally rendered HDR composite video to the operator.
 18. The welding mask of claim 17, wherein the HDR camera subsystem is configured to generate a first HDR video for a right eye of the operator and a second HDR video for the left eye of the operator, and wherein the digital electronic display comprises a stereoscopic display to display the first HDR video to the right eye of the operator and the second HDR video to the left eye of the operator. 